Intraocular lenses (also referred to herein as IOLs or simply as lenses) are artificial lenses used to replace natural crystalline lenses of eyes when the natural lenses are diseased or otherwise impaired. Under some circumstances a natural lens may remain in an eye together with an implanted IOL. IOLs may be placed in either the posterior chamber or the anterior chamber of an eye.
IOLs come in a variety of configurations and materials. Various instruments and methods for implanting such IOLs in an eye are known. Typically, an incision is made in a patient's cornea and an IOL is inserted into the eye through the incision. In one technique, a surgeon uses surgical forceps having opposing blades to grasp the IOL and insert it through the incision into the eye. While this technique is still practiced today, more and more surgeons are using IOL injectors which offer advantages such as affording a surgeon more control when inserting an IOL into an eye and permitting insertion of IOLs through smaller incisions. Smaller incision sizes (e.g., less than about 3 mm) are preferred over larger incisions (e.g., about 3.2 to 5+ mm) since smaller incisions have been associated with to reduced post-surgical healing time and reduced complications such as induced astigmatism.
Injectors come in many configurations, for example an injector may be configured such that the IOL is loaded directly into the body of the injector. Alternatively, an injector may comprises a cartridge into which an IOL is loaded and an injector body into which the cartridge, with the IOL inside, is loaded. The cartridge and/or injector body may be made of disposable or reusable materials.
Conventional IOL cartridges include a load chamber connected to a nozzle. In some configurations, the nozzle includes a small diameter distal tip that is insertable into the eye for delivery of the IOL into the eye. After mating the cartridge with the injector body, a plunger may be translated or screwed through the lumen of the cartridge to urge the IOL through the load chamber and the nozzle into an eye.
In order for an IOL to fit through an incision, it is typically folded and/or compressed prior to entering an eye where it will assume its original unfolded/uncompressed shape. Folding and compression can occur prior to, during or after the IOL is loaded into the cartridge (e.g., using forceps or movement through a tapered nozzle). Since IOLs are very small and delicate articles of manufacture, great care must be taken in their handling, both as they are loaded into an injector and as they are injected into patients' eyes.
It is important that an IOL be expelled from the tip of the IOL injector and into the eye in an undamaged condition and in a predictable orientation. Should an IOL be damaged or expelled from the injector in an incorrect orientation, a surgeon may need to remove or further manipulate the IOL in the eye, possibly resulting in trauma to the surrounding tissues of the eye. To achieve proper delivery of an IOL, consistent loading of the IOL into the injector device with a minimum opportunity for damaging the IOL is desirable.
In general, the IOL is provided to the surgeon in packaging, such as a vial, plastic blister package, or other container for maintaining the IOL in a sterile condition. The IOL is removed from the packaging and loaded into the load chamber of the cartridge prior to insertion into the patient's eye. Removal of the IOL from the packaging and transfer to the load chamber is usually accomplished with forceps or a similar device. The forceps may simply be used to place the IOL on or in the load chamber of the cartridge, or may also fold the IOL to a reduced size for insertion into the eye.
Certain problems may be encountered during delivery of the IOL from the cartridge and into an eye. For instance, during movement though the cartridge lumen, the orientation of the optic and haptic portions may be difficult to control especially if the IOL is folded or compressed inside the nozzle. In addition, problems may be encountered during engagement of the tip of the plunger with the IOL, resulting in damage of optic, haptics, or both.
In view of the above, there is a need for a cartridge that more effectively receives and manages passage of an IOL therethrough.